Fig. 2

a Neurofeedback (NF) performance. Z-transformed EEG power for the two feedback frequency bands (SMR or UA) over the six NF training runs, presented separately for the two patient groups and two control groups. Values were averaged over all repeated NF training sessions. The regression lines for each group are indicated by finer lines. b Feedback screen. The amplitude of the relevant feedback frequency (either SMR or UA) was represented by the bar in the middle of the screen. The two smaller bars on the left and on the right side of the screen represented the inhibit bands (eye blinks or eye movements, muscle activity). The horizontal lines represented the individually defined thresholds for each bar (for details see methods section). The counter at the bottom indicated the number of reward points accumulated during the feedback runs: it increased whenever the middle bar was above and the left and right bars were below their individually defined thresholds